Step 5: Create folder and Set folder permission (Step 7 on Redmine Installation Guide)
make a folder called \tmp and \public\plugin_assets under [Redmine Path]

cd [Redmine Path]
md tmp
md public\plugin_assets

and assign tmp, files, log, public\plugin_assets IWAM account ( or Network Service account) has full control

Step 6: Create Database
Just create database, user account and password (Step 3 on Redmine Installation Guide).
make sure the default database character is “utf-8” because the create database script did not assign.